Singapore stocks finished lower on Friday, with the benchmark Straits Times Index (STI) down 6.71 points, or 0.21 percent, to close at 3,138.08. A total of 4.59 billion shares changed hands with turnover of 1. 23 billion Singapore dollars (986.4 million US dollars). Losers outnumbered gainers 395 to 91, while 472 others finished unchanged. The STI lost 7.79 points, or 0.25 percent, to close at 3,144.79 on Thursday.